K-shell photoionization of ground-state Li-like boron ions [B$^{2+}$]: Experiment and Theory

摘要

Absolute cross sections for the K-shell photoionization of ground-stateLi-like boron [B$^{2+}$(1s$^2$2s $^2$S)] ions were measured by employing theion-photon merged-beams technique at the Advanced Light Source synchrotronradiation facility. The energy ranges 197.5--200.5 eV, 201.9--202.1 eV of the[1s(2s\,2p)$^3$P]$^2$P${\rm ^o}$ and [1s(2s\,2p)$^1$P] $^2$P${\rm ^o}$resonances, respectively, were investigated using resolving powers of up to17\,600. The energy range of the experiments was extended to about 238.2 eVyielding energies of the most prominent[1s(2$\ell$\,n$\ell^{\prime}$)]$^2$P$^o$ resonances with an absolute accuracyof the order of 130 ppm. The natural linewidths of the [1s(2s\,2p)$^3$P]$^2$P${\rm ^o}$ and [1s(2s\,2p)$^1$P] $^2$P${\rm ^o}$ resonances were measuredto be $4.8 \pm 0.6$ meV and $29.7 \pm 2.5$ meV, respectively, which comparefavourably with theoretical results of 4.40 meV and 30.53 meV determined usingan intermediate coupling R-matrix method.